Income Taxes - Additional information (Detail) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Jan. 01, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes
Income tax expense at U.S. federal statutory rate	21.00%		35.00%	35.00%	35.00%
Net reduction in income tax expense due to Tax Cuts and Jobs Act			$ (529)
Re-measurement of net deferred tax assets and liabilities due to tax legislation			(595)
Mandatory transition tax due to tax legislation			$ 66
Mandatory transition tax payment period			8 years
Equity in net losses of unconsolidated entities			$ 68	$ 44	$ 38
Interest expense			363	376	385
Other federal tax credits			13	14	15
Excess tax benefits associated with equity-based compensation		$ 32	37
Reduction in provision for income taxes due to tax audit settlements			2	11	10
Reduction in provision for income taxes due to state net operating losses and credits			12	10	17
Increase (decrease) to accruals and related deferred taxes			(5)	(10)	(18)
Increase (decrease) in provision for income taxes due to impairments			(15)	(15)	(2)
Investments Qualifying for Federal Tax Credits [Member]
Income Taxes
Equity in net losses of unconsolidated entities			30	31	30
Income tax benefit, including tax credits, from equity method investment			$ 51	$ 55	$ 57
2014 Through 2017 [Member]
Income Taxes
Expected time of completion of IRS audits			27 months